Railway traffic controlling apparatus



Nov. 7, 1939. H s, YOUNG A 2,179,462

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Aug. 10, 1938 4 Sheets-Sheet 4 INVENTOR Hen? 3610 157$ ATTORNEY Patented Nov. 7, 1939 UNlTE. s'rrss RAILWAY TRAFFIC CONTROLLING APPARATUS Application August 10, 1938, Serial No. 224,165

26 Claims.

My invention relates to railway traffic controlling apparatus, and more particularly to an interlocking control system for governing the movement of traflic through a track layout comprising a plurality of track sections interconnected by track switches which may be variously arranged to form different trafi'ic routes.

One object of my invention is the provision of an improved all-relay route interlocking system for operating the switches and signals for the different traflic routes by means of levers and push buttons mounted on a track diagram in locations corresponding to the ends of the respective routes in which one or more of the track switches may be operated as required and the signal governing traffic movements over the corresponding route may be cleared by the operation of a lever and push button associated with the entrance and exit ends, respectively, of the representation of that route on the track diagram. A further object of my invention resides in the provision of apparatus for use in systems of this character which is particularly adapted to the control of a variety of different track layouts including those in which there are a plurality of different routes extending between the same route ends. Other objects, purposes and features of my invention will be pointed out as the description proceeds.

My invention is an improvement upon those disclosed in the copending application for Railway traific controlling apparatus, Serial No. 89,602, filed July 8, 1936, by R. A. MoCann and H. S. Young; in the copending applications for Interlocking control apparatus, Serial No. 14,868, filed April 5, 1935 by E. M. Allen andH. A. Thompson; and Serial No. 726,957, filed May 22, 1934 by L. E. Spray; and in the copending applications for Multiple control apparatus, Serial No. 561,422, filed September 5, 1931 by L. E. Spray; and Serial No. 323,286, filed December 3, 1928, by L. E. Spray.

I shall describe three forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

Referring to the accompanying drawings, Figs. 1-A to 1--H, inclusive, taken together, illustrate one form of apparatus embodying my invention. In this form, Fig. 1--A illustrates a typical control panel containing the control levers and push buttons for controlling the apparatus of my invention and includes a track diagram which is a miniature representation of the track layout to be controlled. Fig. 1-D shows, in theupper portion,

55 a plan of the track layout to which the diagram of Fig. 1-A corresponds, while Figs. 1B to 1H, inclusive, taken together, illustrate diagrammatically the circuits for a route interlocking system for controlling the switches and signals of Fig. 1D in accordance with my invention. More 5 particularly, Fig. 1--B shows a route network including circuits by which route relays identified generally by the references N and R, for controlling the track switches, are controlled by the entrance levers E and the exit buttons X of Fig. 10 1A, Fig. 1C shows typical circuits for approach locking relays AS- controlled by the signals. Fig. 1-D shows switch control and indication relays and WP. Fig. 1--E shows the switch locking relays LS which 15 together with the route relays of Fig. 1-B govern relays NWS and RWS for controlling the relays WR of Fig. 1D, and also includes circuits for switch levers W by means of which the track switches may be operated individually. Fig. 1F shows a signal network including circuits for controlling mechanisms G of the signals of Fig. 1-D. Fig. 1G shows circuits for section locking relays ES and WS controlling the relays LS and also the route indicators K of Fig. 1A, the circuits for the latter being shown in Fig. 1 l-I. Fig. 2 shows a modification of the route network of Fig. 1-B, illustrating how the invention may be applied to the different track layout shown in Fig. 2. Fig. 3 shows another modification of the route network of Fig. 1B which illustrates one manner in which the invention may be applied to the track layout of Fig. l.-A when the intermediate signal I2 is omitted.

Similar reference characters refer to similar parts in each of the several views.

In order to simplify the description, I shall first explain the functions of the several parts of my apparatus, and shall then describe its opera tion under selected conditions in detail.

Thetrack switches shown in the track plan of Fig. 1-D are identified by odd numbers I, 3 and 5, and the way-side signals by the even numbers 2, l, 6, 8, Ill and 12. The two switches of a crossover bear the same number but are distinguished by the suffixes A and B, respectively, on the track plan, and, similarly, in the case of multiple arm signals 6 and 8, the suffix A designates the top arm or high speed signal and Ca slow speed signal. The single arm signals 2, 6, l0 and i2 are also slow speed signals. The high speed signals may be cleared only when the track sections in advance are unoccupied, while each slow speed 5 signal serves as a call-on signal which may be cleared to admit a train to an occupied block.

In the circuit plans, each relay or lever is identified by a letter or combination of letters prefixed by the designation of the switch, signal, or track section with which it is associated, and, inorder to enable the circuits to'be morereadily understood, they are arranged in the written circuit form with similar circuits grouped together in the same view. In circuits of this form, the relay contacts are not necessarily shown adjacent the respective relays which operate them, and a contact is identified not only by a number but more particularly by showing the designation of the relay which operates it above the contact. Furthermore, instead of showing the local source of current for energizing the relays, I have shown only the terminals which are designated by the reference characters B and C, referring to the positive or supply terminal and to the negative or common return terminal, respectively, of the source.

To set up a route and clear the corresponding signal, signal 6 for example, the operator rotates the corresponding lever 6E associated with the route entrance on the diagram of Fig. 1A to the right and then pushes the exit button IUX or 8X at the exit end of the representation of the desired route. Levers 2E and E213 are similar to SE, while lever lEiE governing traffic in the opposite direction is similar except that it is arranged to be moved to the left to clear signal ill. Lever lE is a three-position lever which may be moved to the right to clear the high signal 5A or to the left to clear signal 10 when the proper exit button is operated, manual selection as to which of the two signals is to be cleared being effected in this manner. Lever 8E is similarly arranged to clear signal BA or BC when in its left or right-hand positions, respectively.

Each entrance lever E controls an entrance relay ER which when energized connects terminal C of the source to the adjacent end of each route circuit of Fig. 1--B which begins at the corresponding point, there being a route circuit in Fig. 1B for each different route through the track layout. Each exit button X controls the pick-up circuit for an exit stick relay XS which when picked up connects terminal B to the end of each route circuit which ends at the corresponding point, to thereby complete the route circuit having its two ends at the points corresponding to the operated lever and push button and to energize a route relay for each switch of the route. The operation of levers 5E and WK, for example, effects the energization of the route circuit which includes the route relays 3B. and 5BN and the exit relay EQXS, which relays are held energized under the control of the entrance relay BER until lever SE is manually restored to normal. I

Referring now to Fig. 1-D, the track plan shown therein represents the track rails la and lb of each of two main tracks connected by the crossovers l and 5, the lower track being also connected to a siding by a single switch 3. While a specific track layout is disclosed, it is to be understood that the apparatus of my invention is adapted to control other track layouts that may involve entirely different combinations of switches and signals, the present layout having been chosen to illustrate the principles of my invention in a simple manner. As indicated in the drawings, the tracks are divided into sections by insulated joints 7', the detector sections of the upper track which include the track switches bearing the references l1 and ET while those for the lower track bear the references ET and IT. The adjacent approach sections of the two main tracks are designated ST and 4T, respectively. Each track section is provided with the usual closed track circuit including a track battery 9 and a normally energized track relay, in accordance with standard practice, each track relay being identified by the reference character with a numerical prefix identifying the track section to which it corresponds.

Each track switch of Fig. 1-D is actuated by a power operated switch machine SM which, as herein disclosed, may be assumed to be of the type shown in the Zabel Patents Nos. 1,293,290

and 1,413,820. Each switch machine is provided with the usual motor having its operating circuits controlled by the contacts of the polarized switch control relay WR, in the manner illustrated in the Willard Patent No. 1,380,452, as indicated diagrammatically by dotted line connections in the drawings, and it is to be understood that each switch or switches will be operated to normal, as shown, or to reverse, when the control relay WP. is energized and its polar contacts are closed to the left or right, respectively. Each relay WR is controlled by a pair of interlocked stick relays NWS and RWS, as shown in Fig. 1E, and these relays are controlled by the route relays N and R of Fig. 1B when route control is used, or by the corresponding switch lever W when individual switch control is used. The switch stick relays NWS and RW S are also controlled by switch locking relay LS. The locking relays LS are con-- trolled as shown in Fig. 1E by the detector track relays TR of Fig. lD, the approach locking relays AS of Fig. 1-C, and the section locking relays ES and WS of Fig. 1-G.

Each switch machine is provided with the usual switch circuit controller, as disclosed in the Zabel patents hereinbefore referred to, for controlling a polarized switch indication relay WP, as indicated diagrammatically by dotted line connections in Fig. 1D. For an understanding of the present invention it will suffice to point out that when both switch machines SM of the cross-over i or 5 are locked normal or reverse, the corresponding relay IWP or EWP will be energized and its polar contacts closed to the left or right, respectively, and that relay SWP is similarly controlled by switch machine 35M for the single switch 3.

Each switch indication relay WP is provided with a pair of repeating relays NWP and RWP each of which is energized only when the polarized relay WP is energized in a position corresponding to that of the associated switch control relay WR.

As will be hereinafter pointed out in detail, the locking. relays LS together with the switch indication relays NWP and RWP control the route circuits of Fig. 1-13 in such a manner that a route circuit can not be completed unless each switch of the route is either unlocked or already occupies a position in accordance with the route.

Fig. 1F shows a signal network of interconnected circuits for controlling the signa s of Fig. 1D. Each signal has an operating mechanism, designated by the reference character G with identifying prefix in Fig. l.F, and is controlled over a signal circuit which corresponds to the route which such signal governs and which includes contacts of the entrance relay ER, of the route relays N and R and the indication relays NWP and RWP for the route. The signals may be of any desired type, but, as herein illustrated, it is to be understood that they are of the wellknown searchlight type having mechanism G of the form disclosed in the E. J. Blake Reissue Patent No. 14,940 of August 31, 1920.

For simplicity each signal as illustrated is arranged to indicate either clear or stop, and the usual circuits for controlling each signal by the next signal in advance to provide a third indication have been omitted from the drawings since these are not essential to an understanding of the present invention.

Each signal mechanism or group of mechanisms G is provided with an approach locking stick relay such as the relays identified by the reference character AS in Fig. lC. To simplify the drawings only the circuits for the locking relays IZAS and 4AS are shown, but it is to be understood that the circuits for relays ZAS, tAS and WAS are similar to those for relay IZAS while the circuits for relay SAS are similar to those for relay lAS. These relays provide the usual time and approach locking of the switches and of opposing signals; thus when a signal assumes the stop position the energization of the associated relay AS is delayed for a predetermined time interval provided the signal is put to stop manually, this delay being nullified by the release of the corresponding track relay when the signal is automatically put to stop by a passing train. The approach locking relays AS control the section locking relays ES and W S by means of the circuits of Fig. 1-G, which relays provide the usual directional control of the switch locking and function so that when a train enters a route the locking of each switch ahead of the train will be maintained while the locking of each switch in the rear of the train will be released as soon as the corresponding track section is vacated.

The locking relays ES and WS also control the route indication lamps K located in the track diagram of Fig. l-A. The arrangement is such that when a signal is cleared the corresponding approach locking relay AS is released, and this relay in turn deenergizes the section locking relay ES or N S for each section of the corresponding route. The section locking relays upon releasing complete circuits in Fig. 1I-I in accordance with the position of the track switches so as to light selected indicator lamps K to displayan illuminated representation of the established route on the track diagram. The lamps K remain lighted after the train enters the route and are extinguished successively when the section locking relays pick up as the corresponding track sections are vacated.

Since, as hereinbefore mentioned, the route network of Fig. l-B corresponds in form to the actual track layout, it may occur that it provides a plurality of different circuit paths between the same route ends, certain of which do not correspond to available traffic routes, such asthe one, for example, from signal 8 to signal 5 over switch 5A normal, and switches lA, i3 and l reversed. One feature of my invention resides the provision of means for preventing the energization of the route relays in such circuits as provided, for example, by including back contacts of relays BER and EXS in the circuit path referred to. In other cases, there may actually be two available routes between the same route ends for example, route 8-4 from signal. to signal d over switch 5A normal and svfltches EA and 5B reversed, or over switches 5A and 5B reversed and switch IB normal. The first of these is the preferred route because it does not interfere with train movements over the parallel route 6-l ll, and normally is the one that is rendered available in response to the operation of lever 8E and button 4X. However, the arrangement is such, as will hereinafter be explained in detail, that under certain conditions which prevent the establishment of the preferred route the alternative route over switches 5A and 5B reversed and switches 3 and 113 normal becomes established when lever 8E and button 4X are operated.

I shall now describe the operation of my apparatus under different assumed conditions. I shall first assume that the apparatus is in the condition shown in the drawings and that the operator desires to pass a train from section dT, Fig. l-D, over the preferred route d-% which extends over switches 1B and Hi reversed, past signal [2 and over switch 5A normal to section 8T.

To set up the preferred route l il for a movement from left to right, the operator will first set up route 4l-l2 and then set up route !23, that is, he will first operate levers 4E to the left and will then press button l2X momentarily. This operation of lever 4E completes a circuit for relay iCER which may be traced in 1-B from terminal B, contact l of lever ill, relay lCER, back contact I! of relay dXS to terminal C.

When button UK is operated, a circuit is closed from terminal B, relay l2XS, contact is, back contact M of relay BEP to terminal C. Relay lZXS picks up, but the route relay 51 2. does not pick up at this time because, although terminal C is connected both to the left-hand terminal of its winding over front contact l5 of relay lCER, it is also connected to the right-hand terminal of its winding over contacts it, it and id, so that there is no diiference of potential between the two ends of the route circuit including relay ER. When button I2X is released to open contact i3, relay IR picks up over the route circuit extending from terminal B, the winding and front contact iii of relay lZXS, relay iR, back contacts H, i8, i9 and 2d of relays lAN. lBN, QXS and ZER, front contact 21 of relay lLS, hack contact 22 of relay iXS, front contact is of relay GCER to terminal C. Relay IE will thus he held energized in series with relay iZXS as long as lever all is reversed, and by opening its back contacts 23, 24 and ill will prevent the energization of the route circuits for the conflicting routes 2-!2, l8 and 4lll. Relay IR also closes contact 26, Fig. 1-E, completing a circuit from terminal B, contacts 25 and 26 of relays ELS and 5B, relay lRWS to terminal 0. Relay IRWS accordingly picks up, opening contact ill to release relay INWS. Relay INWS, upon releasing, completes a stick circuit for relay IRWS at its contact 22, and also completes a circuit from terminal B, front contact 29 of relay lRWS, relay lWR. hack contact as of relay ENWS to terminal C. Relay lW therefore reverses and operates the switch machines lASM and iBSM to reverse switches i, and also open its left-hand polar contact 3!, Fig. lD, to release relay ENWP.

Relay INWP, upon releasing, opens various front contacts in the circuits of Figs. l-B, l-E, l--F, l-G and l--H.

When the switches 5 complete their movement and become locked reverse, the polarized switch indication relay lWP, Fig. l-D, becomes energized in the reverse direction, completing a circuit from terminal B over its neutral contact 32 and reverse polar contact 33, relay IRWP, and reverse contact 3i of relay IWR to terminal C.

Relay IRWP therefore picks. up and closes contacts in the circuits of Figs. 1B, 1--E 1F and 1-H. In Fig. 1E, the normal indication lamp INK for the switches I is extinguished and the reverse indication lamp IRK becomes lighter, and in Fig. 1-F, a circuit is completed from terminal B, over front contacts 34, 35 and 36 of relays I2XS, IRWP and IR, back contact 31 of relay lAE-R, front contact 38 of relay dCER, the winding of the signal mechanism 40G, back contact 39 of mechanism GAG, and front contact 40 of relay lCER to terminal C. Mechanism tCG therefore becomes energized to cause signal 4C to indicate proceed at slow speed.

Mechanism lCG, upon becoming energized, opens contact il, Fig. 1-0, in the circuit for relay IAS, so that relay lAS releases and opens contact 42, Fig. l-E, to deenergize relay ILS. Relays I LS releases and opens its front contacts including contacts 25 and 43, Fig. 1E, in the pick-up circuits for relays IRWS and INWS- to lock switches I reversed, and at its back contact 43 completes a circuit for lamp LK over front contacts 34 and 45 of the track relays ITK and UK, lighting lamp LK to indicate to the operator the locked condition of switches I.

Relay IAS, upon releasing, also opens contact 46, Fig. lG, deenergizing relay 'IES. Relay 'IES releases and opens contacts 47 and 48, Fig. 1-G, in the circuits for relays IE8 and 3E8. Relay IE8 is thereby released, but relay 3ES does not release because contact 48 is now bridged by contact 49 of relay IRWP. Relays IES and IES at their back contacts 50, 5I and 52, Fig. 1-4-1, complete circuits to light the route indicator lamps IBK, IRK and IAK, respectively, in the track diagram of Fig. 1A, thereby indicating the established route il2 on the diagram.

It will be noted that in Fig. 1B the circuits for routes conflicting with route 4I2 are now open at contacts 53 and 54 of relay ILS and contacts 55 and 56 of relay INWP but that the circuit for route 4I2 is now maintained closed at contact 51 of relay IRWP although contact 2| of relay ILS is open, so that signal 4C will be held at clear until lever 4E is restored to normal.

I shall now assume that the operator moves lever IZE to the right and operates button 8X momentarily, to clear signal I2. The operation of button 8X completes a pick-up circuit from terminal B over back contacts 58 and 59 of relays 8AER and BCER, front contact 60 of relay BAS, relay 8X8, contact 6| of button 8X to terminal C. Relay BXS picks up and when button 8X is released the route circuit for route I2-8 is energized from terminal B over contacts 58, 59 and 60, the winding and front contact 52 of relay 8X3, the Winding of relay 5AN, back contact 63 of relay 5R, front contact 64 of relay 5LS, back contact 65 of relay BEP, relay I2ER, right-hand contact 66 of lever IZE, back contacts 61 and 88 of relays 8CER and BAER to terminal C. Relays IZER and 5AN pick up, and relay BXS is held energized over the circuit just traced, under the control of lever IZE. Relay 5AN opens contact 69 in the conflicting route circuit for relay ER, and, in Fig. 1E closes contact I0 in the pick-up circuit for relay BNWS. Relay 5WR therefore remains energized in the normal direction, and, in Fig. 1F, a circuit is completed from terminal B, front contact 'II of relay BXS, back contacts I2 and 73 of relays 8CER and BAER, front contacts I4, 15 and 16 of relays 5NWP, 5AN and iZER, mechanism IZG, contact TI of relay IZER to terminal C. Mechanism IZG therefore becomes energized to clear signal I2.

Mechanism IZG upon becoming energized opens contact I8, Fig. lC, in the circuit for relay IZAS, releasing relay IZAS to open contact I9, Fig. 1E, in the circuit for relay 5L8. Relay 5LS therefore releases and locks switches 5 normal, and, in Fig. l-B, opens contacts in the route circuits for all routes over switches 5. Relay 5LS at its back contact 80, Fig. lE, completes the circuit for lamp 5LK. It will be noted that the opening of contact 84 in the route circuit for route I28 is without effect because that contact is bridged by contact 8| of relay 5N'WP. Relay I2AS also opens contact 82, Fig. 1G, releasing relay 5ES, which relay at its back contact 83, Fig. lH, completes circuits to light the route indicator lamps 5ANK and 5AK in the track diagram of Fig. l-A, indicating to the operator that the portion I 28 of the route 4-8 has been established.

I shall now assume that the approaching train passes signal 50 at clear and enters track section IT. Track relay 'ITR releases and at contact 68 opens the circuit for the stick repeater relay ITS which releases. Relay ITR at its back contact 45, Fig. 1-43, connects lamp ILK to terminal C over the back contact 84 of a continuously operating interrupter relay CT. Lamp ILK therefore will display a flashing indication, indicating the occupancy of section IT or IT, and the operator will restore lever 4E to normal, releasing relays ICER, IR and IZXS and consequently deenergizing mechanism 4CG to cause signal 10 to indicate stop and to close contact M, Fig. 1-0, to reenergize relay 4A8. Relay 4AS picks up over a circuit from terminal B, contacts I33 and 4| of mechanisms IAG and 4CG, back contact I50 of relay ITR, normal contact I31 of a thermal relay ATE, relay IAS to terminal C. Relay iAS upon picking up completes its stick circuit which extends to terminal B over contacts I33 and 4| and its own front contact I34. Switches I remain locked because the circuit for relay ILS is now open at contact 85 of relay ITS or at contact 86 of relay ITR, Fig. 1E. When the train vacates section IT, relay ITR picks up and by closing contact 81 reenergizes 'iES, which relay by opening contact 50 causes the route indicator lamp IBK to be extinguished. Relay ITR also closes contact 88, Fig. lD, reenergizing relay ITS. When the train vacates section IT relay ITR picks up and completes the circuit for relay IES, Fig. 1G, at its contact 89. Relay I ES picks up and opens contacts 5| and 52 to extinguish the route indicator lamps IRK and IAK. Relay ITR also closes contact 86, Fig. 1E, reenergizing relay ILS and thereby extinguishing lamp ILK.

The various operations incidental to the movement of the train through the portion IZ-B of the route are similar to those just described, and it is believed they will be readily understood from the drawings without further detailed description.

The route circuits for train movements from right to left are somewhat different from those already described because there is no intermediate signal for that direction. To explain the operation of these circuits I shall assume that lever 8E is moved to the right and button 4X operated momentarily, in order to establish route 84 and to clear signal 3-C. This results in the energization of relays BCER, and 4X8 over circuits similar to those for relays ACER. and 8X8 already traced. When relay fiCER picks up, a circuit is closed in Fig. 1-B from terminal B, back contact 58 of relay BAER, front contact 59 of relay BCER, back contact Slit of relay 5R, front contact 9| of relay lZAS, relay iiEP, back contacts 92 and 93 of relays l2ER and iZXS to terminal C. Relay SEP therefore picks up and when button lXS is released the circuit for route 8& over I reversed becomes energized from terminal B, back contacts 94 and 95 of relays IAER and QCER, front contact 96 of relay 4A8, the winding and front contact 22 of relay lXS, front contact 2| of relay ILS, back contacts 25, i9, I8 and I! of relays 2ER, 2X3, IBN and lAN, relay IR, back contact I5 of relay IZXS, front contacts 65 and E5 of relays HEP and 5L8, back contact 53 of relay 5R, relay 5AN, back contact 52 of relay 8X8, front contact 9'! of relay BCER to terminal C. The route circuit for the alternative route 84 over 5 reversed does not become closed at this time because it includes the open back contact I I3 of relay ECER. Relays IR and 5AN pick up and relay tXS is held energiezd .over the circuit just traced, switches I are reversed and switches 5 held normal as hereinbefore described, and when the route is established a circuit for mechanism G is closed in Fig. l-F from terminal B at contact 98 of relay iXS, contacts 38, 3'5, 36, 35, 34, contact 99 of relay BEP, contacts l6, "I5, 15, back contact 13 of relay EAER, front contact I2 of relay BCER, the winding of mechanism BCG, back contact I50 of mechanism BAG, contact Ifll of relay 8CER to terminal C.

Signal 8C therefore clears, releasing relay 8A8, which relay, as hereinbefore mentioned, is controlled in the same manner as relay 4AS of Fig. 1-0. Relay tAS by opening contact I02, Fig. 1-G, releases relay 5W8, which relay by opening contacts I63 and H14 will selectively, release relay IWS or 3W8, dependent upon the position of switches 5. In this instance, since switches 5 are normal, relay IWS releases and in turn, by opening contact I55, releases relay IWS because switches i are reversed and contact I5I of relay iNW S which normally bridges contact I05 is now open. Relay 5W8 closes its back contact I06, Fig. 1-II, lighting the route indicator lamps 5AK and EANK. Relay IWS at its back contact I01 completes a circuit to light lamp IAK, while relay 'lW S at contacts I98 and I09 completes circuits to light lamp IRK and IBK, thereby indicating the established route on the track diagram. Relay BAS upon releasing also opens a contact IIl'I, Fig. l--E, releasing relay 5L8 and relays IWS and IWS by opening contacts III and H2 release relay ILS.

It will be readily apparent from the drawings that as the train enters route 8-4 and relay 8AS becomes reenergized, the route indicators will be extinguished and the locking for switches 5 and I will be released successively; indicators 5AK and 5ANK becoming extinguished and switches 5 released when section 5T is vacated, IAK becoming extinguished when section IT is vacated and IRK and IBKbecoming extinguished and the looking for switches I released when section IT is vacated.

I shall next assume that the operator is unable to establish route 8 l as described, for the reason that signal 2 has been cleared to permit a train movement from left to right up to signal I2 at stop. The clearing of signal 2 will cause relay ILS to release, and the route circuit traced for route 84 over I reversed will be open at contacts 2I and 51 of relays ELS and IRWP. The open contact N3 of relay SCER in the circuit for the alternative route 8- l over 5 reversed is now bridged by a branch circuit including contacts IM and H5 of relays I2XS and SEP, which is closed because relay IZXS has been picked up to clear signal 2. Back contact l I5 of relay 8EP will be closed because contact 93 of relay IZXS in the circuit for relay BEP is open and relay SEP therefore does not pick up when relay BCER becomes energized.

It follows that in this instance the energization of relay BCER together with the momentary operation of button lXS will complete a route circuit in Fig. l-B from terminal B at contact 94 of relay tAER over contacts and 96, the winding and front contact 22 of relay 4X8, contact 55 of relay INWP, front contact Illc of relay 3L8, back contacts H1, H8, H9 and I29 of relays IR, 3R, 5X8 and GER, relays IBN and 3N, front contact II of relay IZXS, back contacts H5, EZI, I22 and I23 of relays BEP, BAER, IOXS and IllER, front contact I24 of relay 5LS, back contacts 69 and 25 of relays 5AN and 5BN, relay 5R, back contact 52 of relay 8XS, front contact 9'! of relay BCER to terminal C. The energization of relays lBN, 3N and 5R over the route circuit just traced will result in maintaining switches I and 3 normal and reversing switches 5. Furthermore, the route circuit just traced will remain energized even if signal 2 is now restored to stop and relay IZXS released, because contact H4 of that relay is bridged by contact I26 of relay SR and the route circuit for the route 84 over I reversed is maintained open at back contact I8 of relay IBN, and also at back contact 9! of relay 5B. The circuit previously traced in Fig. 1F for mechanism 8CG is now open at contacts 35, 35, 99, I5 and M of relays IR, IRWP, BEP, 5AN and ENWP, but these contacts are now bridged by a branch circuit including corresponding front contacts I52 to I51, inclusive, of relays IBN, INWP, 3N, 3NWP, 5R and 5RWP, as will be apparent from the drawings, so that signal BC will clear.

Since switches 5 are reversed and switches I are normal, it will be apparent from Figs. 1--G and 1--H that when relay SAS releases, relays 5WS,

3WS and lWS will be released successively to light lamps 5AK, 5RK, SNK, lBNK, and lBK to illuminate the representation of the established route on the track diagram.

The alternative route 8-4 over 5 reversed will also be established if the route buttons are operated when section IT is occupied by a train moving over the switch lA normal. In this instance the route circuit will be completed over a branch circuit bridging contact I I3 of relay SCER. which includes front contact I21 of relay INWP and back contact I28 of relay ITR, as shown in Fig. 1B.

I shall next assume that the apparatus is in its normal condition, as shown, and that the operator wishes to clear the high speed signal 8A for a train movement over route 82. He will move lever SE to the left and then operate button 2X momentarily. In this case, relays BAER, HEP, 5AN, IAN and 2XS will become energized, switches I and 5 will be operated to normal, as shown, and signal 8A will clear. Signal 8A as sumes the stop position automatically when a train passes it and enters section 5T, because the circuit for mechanism BAG includes a front contact I29 of the stick repeater relay T8 controlled by track relay 5TB. Relay 5T8 remains deenergized after the train vacates section 5T until lever 8E is restored to normal, for the reason that its pick-up circuit includes a back contact I of relay 3AER as shown in Fig. 1D.

It may happen that the operator is unable to complete a route by operation of the route levers, due to failure of one or more of the track switches to fully operate, as would be the case, for example, if there were an obstruction in a switch. In such case the operator would employ the individual lever W of Fig. 1-E to operate the switch back and forth to remove the obstruction or to restore the switch to its original position.

To do this, it is necessary to first release the energized route relays by restoring the lever for the entrance end of the route to normal.

It will be clear from Fig. 1-13 that the switch stick relays NWS and RWS may be operated to actuate the corresponding relay WR, as required, by momentarily operating the corresponding switch lever W to the right or left, provided the switch locking relay LS for the switch is energized at the time and the route relays are not energized,

and each relay WR when so actuated will control the associated track switch to a corresponding position as already explained, the response of the track switch being indicated in the usual manner by the lighting of lamp NK or RK. This portion of my apparatus is so arranged that the track switches will respond to the movement of a lever W only if such movement is made when the switch locking is released, and the switches will not be operated automatically upon the release of the locking in the event a lever has been previously moved out of correspondence with the existing switch position and the switches have failed to respond because of their locked condition. That is, the apparatus includes means for preventing the so-called storage of a switch operation. It will be apparent from Fig. 1-H that if lever IW, for example, is moved to the left or right when the locking relay ILS is deenergized due to contact 42 of relay 4A5 being open, the subsequent closing of contact 42 will not result in an operation of switches I because the circuit for relay LS will. be open at the lever contact I3I. Lever iW must remain in its center position, as shown, until relay lLS picks up to establish its stick circuit over contact 532, and it follows, therefore, that any operation of lever iW to left or right made while relay iLS is deenergized is ineffective.

It will be apparent that the operator may set up any desired route by the operation of the individual levers W and may then clear the corresponding signal by operating the proper entrance lever and exit button.

A further feature of my invention relates to .eans for preventing a reversal of traffic direction under certain conditions. If signal 4C has been cleared as hereinbefore described to permit a train movement from section 4T to section 8T, relay iAS will be deenergized and will not become reenergized if lever iG is restored to normal before the train enters section IT until after the lapse of the usual time interval measured by the thermal relay l'IE of Fig. 1-0. In this case, when contact M of relay GCG closes, contact I58 of relay 4TB, in the pick-up circuit for relay 4A8 is open, but a circuit is completed from terminal B over back contacts E33, M, I34. and I of relays @AG, G, MS and 'iTES through the heating element of the thermal relay 4TB to terminal 0. Relay ATE will open its contact I31, and at the end of a predetermined heating period, contact 36 of relay -iTE will close to pick up relay I'IES, which relay will then be held energized over its front contact I35 and will deenergize relay fiTE. At the end of a predetermined cooling period relay iTE will close its contact 53! to complete a circuit from terminal B over contacts E33, ll, I38 and I31 of relays iAG, 40G, TES and ITE, through relay tAS to terminal C, so that relay GAS will pick up and complete its stick circuit over contact 53:1 and deenergize relay QTES. This prevents the operation of the track switches in the face of an approaching train in the usual manner, and, in addition, delays the reversal of the direction of the movement of track over the route because contact 96 of relay 0A8 in the pick-up circuit for relay 4X8 remains open until the time interval measured by relay iTE is completed.

Although I have in the foregoing traced but a few of the many possible operations of my apparatus, it is believed that the operation of setting up each of the remaining routes will be readily understood from the drawings Without further explanation.

Referring now to Fig. 2, I have shown a different track layout including three routes between signals l and 8, For simplicity, all of the signals are shown as slow speed signals, but the route circuits in the lower portion of Fig. 2 are in other respects generally similar to those of Fig. 1-B. Of the three routes between signals 4 and 8, the one over switches 'I reversed has been chosen as the preferred route for movements from left to right and the one over switches l reversed as the preferred route for movements from right to left. Normally, all these three route circuits are open, the preferred routes mentioned being selected by the closing of contact I39 of relay SXS or contact 1% of relay XS in response to the operation of the respective exit,

buttons 8X or @X. In Fig. 2, relay 8XS controls two slow pick-up relays BXP! and 8XP2 which pick up successively at time spaced intervals when relay ElXS becomes energized, and relay 4X8 similarly controls two slow pick-up relays iXPI and lXPi'i, and since the operation in the two directions is similar, only that for movements from. left to right will be described. I will first assume that lever E is moved to the right and that button 8X is operated momentarily. This normally will result in completing a route circuit for route 43-8 over I reversed, as will be readily understood in View of its similarity to the circuits of Fig. l-B already described, this circuit including the relays IBN, 5BN, JR and 8X8. If new this preferred route 84 over I reversed fails to become established in response to the operation of button 8X or lX for any reason, button 8X may be operated again and held closed for a time sufficient to cause relay SXPI to pick up.

Back contact MI of relay BXPI will now open to prevent the subsequent closing of the preferred route circuit, and front contact I24 of relay SXPI will close to prepare the circuit for the alternative route 8@ over switches reversed. If this alternative route circuit fails to become energized upon the release of button 8X after relay 8XP! is picked up, the button may be closed again and held closed until relay 8XP2 picks up. Back contact M3 of relay EXPE will open to prevent the closing of the circuit for route 48 over switches 5 reversed, and contact Hi l of relay XP2 will close to prepare the circuit for the second alternative route 84 over switches I reversed.

Til

It will be clear that since in each case the route circuit does not become energized until the exit button is released, the operator may select manually any one of the three routes by a single operation of the exit button, the particular route selected being dependent solely upon the length of time the button is held in its operated posiion. It is obvious that suitable indication means controlled by the relays XP may be provided to indicate which of these relays is picked up in order to inform the operator as to which route will be completed upon the release of the button at any time during the operation of these relays.

In Fig. 3 I have shown the same layout as that controlled by the first form of the apparatus except that the intermediate signal i2 is omitted and all the signals are shown as slow speed signals for simplicity. It will be remembered that in Fig. 1-B there are in some instances multiple circuit paths between the same route circuit ends, for example, from terminal B at back contact 58 of relay llAER one circuit may be traced through relays BXS, 5R and BE, and another through relays BXS, SAN, lR, lBN, 3N and 3R to terminal C at contact M5 of relay @ER. The closi g of the last-mentioned circuit, which obviously does not correspond to any available route, is avoided, when relay BXS or BER is operated, because it includes back contacts HQ and i211 of these relays. Similar contacts are included in each circuit of a correEponding nature in Fig. l- -B. In Fig. 3, the necessity for these additional checking contacts is avoided by arranging the circuits so that the flow of current is always in the same direction, that is, as shown, from terminal B at the left to terminal C at the right, and by including asymmetric units, preferably of the copper oxide rectifier type, in certain of the circuits so as to permit the fiow of current only in the desired direction. Thus for example, in Fig. 3, current may flow from terminal B at contact M6 of relay this through relays 3R, R and 8X8 to terminal C, while the flow of current through the branch around relay 5R including relays 3N, lBN, ER and EAN is blocked by the asymmetric unit Ml.

It will be evident from the drawings that the three units Mi, his and M9 in Fig. 3 prevent the energization of any undesired circuit path of the type described in the layout.

Although I have herein shown and described only three forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In an interlocking control system, a track layout including a plurality of track switches which may be arranged to form different trafic routes, a normal and a reverse control relay and a locking relay for each switch, manually operable contact rneans for the ends of said routes, a route network including a route circuit for each route, each such circuit including the normal or reverse control relay and a front contact of the locking relay for each switch of such route, means for energizing each route circuit to pick up the normal or reverse control relays as required to establish such route when the contact means for its two ends are operated, switch indication relays indicating the positions of the track switches, means comprising contacts of said indication relays for bridging the locking relay front contacts in the route circuit for each route only when the corresponding switches occupy the positicns required for such route, and means deener-gizing the locking relay for each switch of a route when such route is fully established to isolate the energized route circuit from all confiicting route circuits.

2. In an interlocking control system, a track layout including a plurality of track switches which may be arranged to form different traffic a locking relay for each switch, manually operable contact means for the ends of said routes, a route network including a route circuit for each route, each such circuit including the normal or reverse control relay and a front contact of the .10 routes, a normal and a reverse control relay and the corresponding switches occupy the positions required for such route, signals for governing trafiic movements over said routes, means for clearing the signal governing trafilc movements over that route having its route circuit energized when such route is fully established, and means deenergizing the locking relay for each switch of a route when the signal governing traiiic movements over such route is cleared.

3. In an interlocking control 5 "stem, a track which may be arranged to form different traffic routes, a normal and a reverse control relay and a locking relay for each switch, manually operable contact means for the ends of said routes, a route network including a route circuit for each route, each such circuit including the normal or reverse control relay and a front contact of the locking relay for each switch of such route, means for energizing each route circuit to pick up the normal or reverse control relays as required to establish such route when the contact means for its two ends are operated, switch indication relays indicating the positions of the track switches, means comprising contacts of said indication relays for bridging thelocking relay front contacts in the route circuit for each route only when the corresponding switches occupy the positions required for such route, signals for governing trafiic movements over said routes, means for clearing the signal governing trafiic movements over that route having its route circuit energized when such route is fully established, means deenergizing the locking relay for each switch of a route when the signal governing traffic movements over such route is cleared, and means reenergizing each locking relay when a train governed by such signal has passed fully over the corresponding track switch.

4. In an interlocking control system, a track layout including a plurality of track switches.

which may be arranged to form diiierent traffic routes, signals for governing traffic movements over said routes, 9. normal and a reverse control relay for controlling and a locking relay for lock ing each switch, normal and reverse indication contacts controlled by each switch and closed only when the switch occupies the corresponding nor mal or reverse position, a route network including a route circuit for each route each such circuit including the normal or reverse control relay for :afi layout including a plurality of track switches each switch of the route and in series therewith the indication contact for each switch of the route which is closed when such switch occupies a posi tion in accordance with the route and in multiple with such contact, a contact of the locking relay for the corresponding switch which is closed when the switch is not locked by such relay, and means for energizing each route circuit to pick up the normal or reverse control relays as required to establish the corresponding route and to clear the signal for such route when fully established.

5. In an interlocking control system, a track layout including a plurality of track switches forming different traflic routes certain of which conflict with others, a route network including a route circuit for each route, a manually operable relay for each route end, means responsive to the energization of the manually operable relays for the opposite ends of a route to energize the route circuit for said route, means comprising a back contact of one of said relays included in the route circuit for a route conflicting with the route governed by said relays for preventing the energization of the route circuit for such conflicting route when said one relay is energized, and means controlled by the energized route circuit for operating the track switches as required to establish the corresponding route.

6. In an interlocking control system, a track layout including a plurality of track switches which may be arranged to form a plurality of trafiic routes said layout including two alternative routes between the same route ends, a route network corresponding to said track layout including a route circuit for each route, one or more of such circuits extending from each route end at one end of said network to each route end at the other end thereof, a manually operable relay for each route end, means responsive to the energization of the manually operable relays for the opposite ends of a route to energize the route circult for said route, means including a back contact of the relay for one of the common ends of said two alternative routes for preventing the energization of more than one of the route circuits for said alternative routes when the relays for the opposite ends of such routes are energized, and means controlled by each route circuit when energized for operating the track switches as required to establish the corresponding route.

'7. In an interlocking control system, a track layout including a plurality of track switches forming difierent trafilc routes, a control lever and a push button for each route end, an entrance relay and an eXit relay for each route end, a circuit for each entrance relay closed when the control lever for the same route end is in its operated position and the exit relay for that route end is deenergized, a pick-up circuit for each exit relay closed when the push button for the same route end is operated and the entrance relay for that route end is deenergized, a normal and a reverse control relay for each track switch, a route network including a route circuit for each direction for each route through the track layout each such route circuit including a front contact of the entrance relay for one end of the route, the winding of the normal or reverse control relay for each switch of the route, and the winding and front contact of the exit relay for the other end of the route, and a source of current for energizing each route circuit rendered effective when the pick-up circuit for the exit relay for the corresponding route is opened to actuate the normal and reverse control relays as required to establish such route.

8. In an interlocking control system, a track layout including a plurality of track switches which may be arranged to form different trafiic routes said layout including two alternative routes between the same route ends, a normal and reverse control relay for each switch, a route network including a route circuit for each route each such circuit including in series the normal or reverse control relay for each switch of the route and contacts which open when route circuits for conflicting routes are energized, manually operable means for each route end in said layout, means responsive to the operation of the manually operable means for the two ends of a route to energize the corresponding route circuit to pick up the normal and reverse control relays as required to establish such route, and selecting means comprising contacts included in the route circuits for said two alternative routes and effective to prevent the energization of one but not of the other of said two alternative routes in response to the operation of the manually operable means for the opposite ends of such routes unless a route circuit conflicting with said other alternative route but not with said one route is energized.

9. In an interlocking control system, a track layout including a plurality of track switches which may be arranged to form diflerent traific routes said layout including two alternative routes between the same route ends, a normal and reverse control relay for each switch, a route network including a route circuit for each route each such circuit including in series the normal or reverse control relay for each switch of the route, manually operable means for each route end in said layout, means responsive to the operation of the manually operable means for the two ends of a route to energize the corresponding route circuit to pick up the normal and reverse control relays as required to establish such route, contact means included in the route circuits for said two alternative routes and normally efiective to prevent the energization of one but not of the other, and means for operating said contact means automatically to permit the energization of the route circuit for said one alternative route when a train occupies a route conflicting with said other alternative route but not with said one alternative route.

10. In an interlocking control system, a track layout including a track switch, a locking relay effective when deenergized to prevent the operation of the track switch, a normal and a reverse switch control relay, normal and reverse indication contacts controlled by the track switch to indicate its position, means effective when the normal or reverse switch control relay is energized to operate the switch to a corresponding position. and to maintain it in such position as long as such control relay remains energized, means effective only if a control relay is energized and the corresponding normal or reverse indication contact is closed to deenergize said locking relay, and energizing circuits for the normal and reverse control relays each including the corresponding normal or reverse indication contact and in multiple therewith a front contact of said locking relay.

11. In an interlocking control system, a track layout including a track switch, a locking relay effective when deenergized to prevent the operation of the track switch, a signal for governing with the position of the track-switch, control traffic movements over the switch, normal and reverse indication contacts controlled by the track switch to indicate its position, means effective when the normal or reverse control relay is energized to operate the switch 'to a corresponding position and to maintain it in such position as long as such control relay remains energized, means effective only when a control relay is energized and the corresponding normal or reverse indication contact is closed to clear said signal, means controlled by said signal when clear to deenergize said locking relay, and energizing circuits for the normal and reverse control relays each including the corresponding normal or reverse indication contact and in'multiple therewith a front contact of said locking relay.

12. In an interlocking control system, a track layout including a plurality of track switches, which may be arranged to form different traffic routes, signals at the ends of said routes for governing trafiic movements over said routes, an approach locking relay for each signal, means deenergizing each approach locking relay when the corresponding signal is cleared and for a predetermined time interval after the signal is restored to stop, manually operable entrance and exit relays for each route end, a circuit for each entrance relay including a manually operable contact, a circuit for each exit relay including a manually operable contact and a front contact of the approach locking relay for the same route end, means effective when the entrance and exit relays for the two ends of a route are both energized to operate the track switches as required to establish such route, and a circuit for clearing the signal for such route closed when said route is established by the operation of the track switches and including front contacts'of said energized entrance and exit relays.

13. In an interlocking control system, a track layout including a plurality of track switches which may be arranged to form different trafilc routes, signals at the ends of said routes for governing the movement of trafiic over said routes, including a high speed signal and a slow speed signal at one route end, a control lever and a push button for each route end, an entrance relay for each signal, an exit relay for each route end, means for clearing each signalexcept said slow speed signal when the control lever for the same route end is movedto a given operative position and the push button at the exit end of a route which such signal governs is operated, and means for clearing said slow speed signal when the control lever at the same route end is moved to a different operative position and the push button at the exit end of a route which such signal governs is operated.

14. In combination with a section of railway track including a track switch, a track diagram arranged to represent said section, three lamps mounted on said diagram including one in each branch track on the trailing side of the switch and one in the single track on the facing side of the switch, a normal and a reverseindication relay controlled by the track switch and energized only when the track switch is in a corresponding position, a locking relay which when deenergized prevents operation of the track switch, a circuit controlled by a back contact of said locking relay for lighting said single track lamp, circuits controlled by a back contact of said locking relay and by front contacts of said normal and reverse indication relays respectively for selectively lighting one branch lamp or the other in accordance means for establishing traffic routes over said track switch, and means releasing said locking relay when a traflic route over said track switch is established.

' 15. In an interlocking system for railroads, a track layout comprising a plurality of track sections interconnected by track switches to form different trafiic routes, a track diagram arranged to represent said layout, a plurality of route indication lamps mounted in the tracks of said diagram, a normal and a reverse indication relay controlled by each track switch and energized only when the track switch is in a corresponding position, a locking relay for each direction for each track section, control means for establishing different trafiic routes through said track layout, means effective when any trafiic route is established in either direction for releasing the locking relay for the same direction for the track section at the entrance to said route,

means selectively controlled by the switch indication relays for selectively releasing the locking relays for the same direction for each of the remaining sections of said route, each in response to the release of the locking relay for the preceding section, circuits controlled by back contacts of said locking relays for lighting those lamps in corresponding sections of the track diagram located in the single track portions adjacent the facing side of a switch, and circuits controlled by back contacts of said locking relays and by front contacts of said normal and reverse indication relays respectively for selectively lighting these lamps in the corresponding sections of the track diagram located on the track diagram adjacent the trailing side of a switch each in accordance with the position of the corresponding track switch.

16. In combination with a detector section of railway track including a track switch, a track relay for said detector section, a manually operable circuit controller having a normal and a reverse position and a center position, a locking relay, a pick-up circuit for said locking relay controlled by a front contact of said track relay and a contact closed only when said circuit controller occupies its center position, a stick circuit for said locking relay controlled by said track relay for maintaining the locking relay energized when said circuit controller occupies its normal or reverse position, and circuits for operating the track switch to its normal or reverse position including front contacts of said locking relay and contacts closed when said circuit controller is moved to the corresponding normal or reverse position.

17. In an interlocking system for railroads, a track layout including a plurality of track switches which may be arranged to form different traflic routes, said layout including a plurality of alternative routes between the same route ends, manually operable contact means for the ends of said routes, a route circuit for each route, timing means controlled by the contact means for one end of said alternative routes for selecting the route circuit for a particular one of said alternative routes for energization depending upon the length of. time said contact means is maintained in its operated condition, means responsive to the operation of the contact means for the two ends of a route to energize the corresponding route circuit, and means controlled by each route circuit when energized to operate corresponding route.

1 8. In an interlocking control system, a track layout including parallel tracks connected by track switches which are manually controllable to form different traffic routes a locking relay for each switch controlled by traffic conditions,

a route network corresponding to said track layout and comprising a plurality of interconnected circuits including a route circuit for each traffic route through said layout, manually operable contact means for the ends of the routes, means responsive to the operation of the contact means for the two ends of a route to energize the corresponding route circuit, provided either that the locking relay for each switch of the route is energized or that such switch occupies the position required for the route, means comprising asymmetric units included in portions of said route circuits to prevent the diversion of current from an energized route circuit to interconnected portions of other route circuits, and means controlled by each route circuit when energized to operate the track switches as required to establish the corresponding route.

19. In combination with a railway track switch, a locking relay which when deenergized prevents operation of the switch, a control lever having an inactive position and a normal and a reverse control position, a pick-up circuit for said locking relay controlled by traific conditions and including a contact closed by said lever in its inactive position, a stick circuit for said locking relay independent of said lever contact, and means for operating the track switch to normal or reverse effective when the lever is moved to its corresponding control position provided said locking relay is energized.

20. In an interlocking system, a track layout comprising a plurality of track sections interconnected by track switches to form different traffic routes, a normal control relay and a reverse control relay for each switch, a route network comprising a plurality of interconnected circuits each corresponding to one of said routes and each of which includes in series the winding of the normal or reverse control relay for each switch in the corresponding route, a manually operable relay for each route end at each end of said network, means responsive to the successive energization of the manually operable relays at the opposite ends of a route to energize the network circuit for said route thereby operating the switch control relays to establish said route, and means including a back contact of one of said manually operable relays for opening the network circuit for a conflicting route,

21. In combination, a track layout including a plurality of track switches, a locking relay for each switch effective when deenergized to prevent operation of the switch, a signal-for govern.- ing the movement of trafiic over a particular route through said track layout, a route relay for each switch of said route effective when energized to operate that switch to a position in accordance with said route, a route circuit for said route including all said route relays in series and also including a front contact of the locking relayfor each switch of the route, each said front contact being bridged by a contact controlled by the corresponding switch and closed only when the switch is in a position in accordance with said route, means controlled over said route circuit for clearing said signal when said route is fully established, and means controlled by the signal when clear for releasing the locking relay for each switch of said route.

22. In combination, ;a track layout including a plurality of track switches, a locking relay for each switch effective when deenergized to prevent operation of the switch, a manually operable contact for each track at each end of the layout, a route circuit for each traific route through the track layout including relay means which when energized is effective to operate each switch of the route to a position in accordance with that route, means including the manually operable contacts for the two ends of each route for energizing the corresponding route circuit, means preventing the energization of a route circuit when such two contacts are closed unless each locking relay for a switch of the route is energized or the switch which such locking relay controls is already in the proper position to establish said route, and means for deenergizing the locking relay for each switch of a route when such route is fully established.

23. In combination, a track layout including a plurality of track switches, a locking relay for each switch efiective when deenergized to prevent operation ofthe switch, a manually operable contact for each track at each end of the layout, a route circuit for each traffic route through the track layout including relay means which when energized is effective to operate each switch of the route to a position in accordance with that route, and which also includes a front contact of the locking relay for each switch of the route, means including the manually operable contacts for the two ends of each route forv energizing the corresponding route circuit, and means for deenergizing the locking relay for each switch of a route when such route is fully established.

24. In combination, a track layout including a plurality of power operated track switches, a control relay'for each switch for controlling its operation, a locking relay for each switch effective when deenergized to prevent the operation of the control relay for that switch, a manually operable contact for each track for each end of the track layout, a route circuit for each traffic route through the track layout including relay means for operating the control relay for each switch of the route to establish that route, which circuit also includes a front contact of the locking relay for each switch of the route, means including the manually operable contacts for the two ends of each route for energizing the corresponding route circuit, and means for deenergizing the locking relay for each switch of a route when such route is fullyestablished.

25. In combination, a track layout including a plurality of power operated track switches, a control relay for each switch for controlling its operation, a locking relay for each switch effective when deenergized to prevent the operation of the control relay for that switch, a manually operable contact for each track for each end of the track layout, a route circuit for each traffic route through the track layout including relay means for operating the control relay for each switch of the route to establish that route, which circuit also includes a front contact of the locking relay for each switch of the route bridged by a contact closed only when the switch occupies a position in accordance with that route, means including the manually operable contact for the two ends of each route for energizing the corresponding route circuit, and means for deenergizing the locking relay for each switch of the route when such route is fully established.

26. In an interlocking system for railroads, a

track layout including a plurality of track switches arranged to form a plurality of difierent traffic routes including two alternate routes between the same points at the ends of the track layout comprising a preferred route and a secondary route, a plurality of signals for governing traffic movements over said routes, a manually operable contact for each route end and at each end of the layout, a route circuit for each route,

10 means responsive to the joint operation of the contacts for the opposite ends of a route to energize the route circuit for that route, said means being normally effective in the case of said alternative routes to energize the route circuit for said preferred route only, means controlled by each route circuit when energized to operate one or more of the track switches as required to establish the route and to clear the signal for that route, and time controlled means rendered effective when the contacts at the ends of said alternate routes are operated if the preferred route does not become established within a predetermined time to open the route circuit for that route and to clos-ethe route circuit for said DISCLAIMER 2,17 9,462.Henry S. Y oang, Wilkinsburg, Pa. RAILWAY TRAFFIC CONTROLLING APPARATUS. Patent dated November 7, 1939. Disclaimer filed December 11, 1940, by the assignee, The Union Switch and Signal Company. Hereby disclaims the subject matter of claims 13 and 22.

[Ofiicial Gazette January 7, 1.941.]

DISCLAIMER Wilkinsburg, Pa. RAILWAY TRAFFIC CONTROLLING AI- 2,179,&62.-Hena"y S. Y 0ung,,

PARATUS. Patent dated November 7, 1939. Disclaimer filed June 19, 194:1, by the assignee, The Union Swe'toh and Signal O'ompany.

Hereby disclaims the subject matter of claims 8 and 9.

[Ofiicial Gazette J uly 15, 1941.] 

